Finding alternate storage locations to support failing disk migration

ABSTRACT

A computing device includes an interface configured to interface and communicate with a dispersed storage network (DSN), a memory that stores operational instructions, and processing circuitry operably coupled to the interface and to the memory. The processing circuitry is configured to execute the operational instructions to perform various operations and functions. The computing device detects a potentially adverse storage issue with a memory device of a storage unit (SU) of set(s) of storage unit(s) (SU(s)). The computing device also determines whether to transfer at least one EDSs (associated with the memory device) to another memory device for temporary storage therein. Based on a determination not to transfer, the computing device identifies at least one alternate storage location and facilitates transfer of the at least one EDSs for temporary storage therein. When the potentially adverse storage issue has subsided, the computing device facilitates transfer of the at least one EDSs back.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. § 120 as a continuation-in-part (CIP) of U.S. Utility patentapplication Ser. No. 15/673,978, entitled “STORING DATA IN A DISPERSEDSTORAGE NETWORK,” filed Aug. 10, 2017, pending, which claims prioritypursuant to 35 U.S.C. § 120 as a continuation of U.S. Utilityapplication Ser. No. 14/876,154, entitled “STORING DATA IN A DISPERSEDSTORAGE NETWORK,” filed Oct. 6, 2015, issued as U.S. Pat. No. 9,774,684on Sep. 26, 2017, which claims priority pursuant to 35 U.S.C. § 119(e)to U.S. Provisional Application No. 62/086,611, entitled “MAINTAININGDATA INTEGRITY IN A DISPERSED STORAGE NETWORK” filed Dec. 2, 2014, allof which are hereby incorporated herein by reference in their entiretyand made part of the present U.S. Utility Patent Application for allpurposes.

U.S. Utility application Ser. No. 14/876,154 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part (CIP) of U.S.Utility application Ser. No. 14/792,577, entitled “DISPERSED STORAGEWRITE PROCESS,” filed Jul. 6, 2015, issued as U.S. Pat. No. 9,354,974 onMay 31, 2016, which is a continuation of U.S. Utility application Ser.No. 13/863,475, entitled “DISPERSED STORAGE WRITE PROCESS,” filed Apr.16, 2013, issued as U.S. Pat. No. 9,092,140 on Jul. 28, 2015, which is acontinuation of U.S. Utility application Ser. No. 12/797,025, entitled“DISPERSED STORAGE WRITE PROCESS,” filed Jun. 9, 2010, issued as U.S.Pat. No. 8,595,435 on Nov. 26, 2013, which claims priority pursuant to35 U.S.C. § 119(e) to U.S. Provisional Application No. 61/230,038,entitled “DISPERSED STORAGE NETWORK VERSION SYNCHRONIZATION,” filed Jul.30, 2009, all of which are hereby incorporated herein by reference intheir entirety and made part of the present U.S. Utility PatentApplication for all purposes.

U.S. Utility application Ser. No. 13/863,475 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part (CIP) patentapplication of U.S. Utility application Ser. No. 12/080,042, entitled,“REBUILDING DATA ON A DISPERSED STORAGE NETWORK,” filed Mar. 31, 2008,issued as U.S. Pat. No. 8,880,799 on Nov. 4, 2014, which is acontinuation-in-part (CIP) of U.S. Utility application Ser. No.11/973,542, entitled “ENSURING DATA INTEGRITY ON A DISPERSED STORAGEGRID,” filed Oct. 9, 2007; and is a continuation-in-part (CIP) of U.S.Utility application Ser. No. 11/403,391, entitled “SYSTEM FOR REBUILDINGDISPERSED DATA,” filed Apr. 13, 2006, issued as U.S. Pat. No. 7,546,427on Jun. 9, 2009, which is a continuation-in-part (CIP) of U.S. Utilityapplication Ser. No. 11/241,555, entitled “SYSTEMS, METHODS, ANDAPPARATUS FOR SUBDIVIDING DATA FOR STORAGE IN A DISPERSED DATA STORAGEGRID,” filed Sep. 30, 2005, issued as U.S. Pat. No. 7,953,937 on May 31,2011, all of which are hereby incorporated herein by reference in theirentirety and made part of the present U.S. Utility Patent Applicationfor all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not applicable.

BACKGROUND OF THE INVENTION Technical Field of the Invention

This invention relates generally to computer networks and moreparticularly to dispersing error encoded data.

Description of Related Art

Computing devices are known to communicate data, process data, and/orstore data. Such computing devices range from wireless smart phones,laptops, tablets, personal computers (PC), work stations, and video gamedevices, to data centers that support millions of web searches, stocktrades, or on-line purchases every day. In general, a computing deviceincludes a central processing unit (CPU), a memory system, userinput/output interfaces, peripheral device interfaces, and aninterconnecting bus structure.

As is further known, a computer may effectively extend its CPU by using“cloud computing” to perform one or more computing functions (e.g., aservice, an application, an algorithm, an arithmetic logic function,etc.) on behalf of the computer. Further, for large services,applications, and/or functions, cloud computing may be performed bymultiple cloud computing resources in a distributed manner to improvethe response time for completion of the service, application, and/orfunction. For example, Hadoop is an open source software framework thatsupports distributed applications enabling application execution bythousands of computers.

In addition to cloud computing, a computer may use “cloud storage” aspart of its memory system. As is known, cloud storage enables a user,via its computer, to store files, applications, etc. on an Internetstorage system. The Internet storage system may include a RAID(redundant array of independent disks) system and/or a dispersed storagesystem that uses an error correction scheme to encode data for storage.

Prior art data storage systems do not provide acceptable means tomonitor for failing storage devices and to ensure that data storedthereon is not lost in the event of failure of those storage devices.the prior art does not provide acceptable means to ensure that datastored on devices that fail or are close to failure is adequatelypreserved.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a dispersed ordistributed storage network (DSN) in accordance with the presentinvention;

FIG. 2 is a schematic block diagram of an embodiment of a computing corein accordance with the present invention;

FIG. 3 is a schematic block diagram of an example of dispersed storageerror encoding of data in accordance with the present invention;

FIG. 4 is a schematic block diagram of a generic example of an errorencoding function in accordance with the present invention;

FIG. 5 is a schematic block diagram of a specific example of an errorencoding function in accordance with the present invention;

FIG. 6 is a schematic block diagram of an example of a slice name of anencoded data slice (EDS) in accordance with the present invention;

FIG. 7 is a schematic block diagram of an example of dispersed storageerror decoding of data in accordance with the present invention;

FIG. 8 is a schematic block diagram of a generic example of an errordecoding function in accordance with the present invention;

FIG. 9 is a schematic block diagram of an embodiment of a dispersed ordistributed storage network (DSN) in accordance with the presentinvention;

FIG. 10 is a flowchart illustrating an example of maintaining dataintegrity in accordance with the present invention; and

FIG. 11 is a diagram illustrating an embodiment of a method forexecution by one or more computing devices in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a dispersed, ordistributed, storage network (DSN) 10 that includes a plurality ofcomputing devices 12-16, a managing unit 18, an integrity processingunit 20, and a DSN memory 22. The components of the DSN 10 are coupledto a network 24, which may include one or more wireless and/or wirelined communication systems; one or more non-public intranet systemsand/or public internet systems; and/or one or more local area networks(LAN) and/or wide area networks (WAN).

The DSN memory 22 includes a plurality of storage units 36 that may belocated at geographically different sites (e.g., one in Chicago, one inMilwaukee, etc.), at a common site, or a combination thereof. Forexample, if the DSN memory 22 includes eight storage units 36, eachstorage unit is located at a different site. As another example, if theDSN memory 22 includes eight storage units 36, all eight storage unitsare located at the same site. As yet another example, if the DSN memory22 includes eight storage units 36, a first pair of storage units are ata first common site, a second pair of storage units are at a secondcommon site, a third pair of storage units are at a third common site,and a fourth pair of storage units are at a fourth common site. Notethat a DSN memory 22 may include more or less than eight storage units36. Further note that each storage unit 36 includes a computing core (asshown in FIG. 2, or components thereof) and a plurality of memorydevices for storing dispersed error encoded data.

Each of the computing devices 12-16, the managing unit 18, and theintegrity processing unit 20 include a computing core 26, which includesnetwork interfaces 30-33. Computing devices 12-16 may each be a portablecomputing device and/or a fixed computing device. A portable computingdevice may be a social networking device, a gaming device, a cell phone,a smart phone, a digital assistant, a digital music player, a digitalvideo player, a laptop computer, a handheld computer, a tablet, a videogame controller, and/or any other portable device that includes acomputing core. A fixed computing device may be a computer (PC), acomputer server, a cable set-top box, a satellite receiver, a televisionset, a printer, a fax machine, home entertainment equipment, a videogame console, and/or any type of home or office computing equipment.Note that each of the managing unit 18 and the integrity processing unit20 may be separate computing devices, may be a common computing device,and/or may be integrated into one or more of the computing devices 12-16and/or into one or more of the storage units 36.

Each interface 30, 32, and 33 includes software and hardware to supportone or more communication links via the network 24 indirectly and/ordirectly. For example, interface 30 supports a communication link (e.g.,wired, wireless, direct, via a LAN, via the network 24, etc.) betweencomputing devices 14 and 16. As another example, interface 32 supportscommunication links (e.g., a wired connection, a wireless connection, aLAN connection, and/or any other type of connection to/from the network24) between computing devices 12 & 16 and the DSN memory 22. As yetanother example, interface 33 supports a communication link for each ofthe managing unit 18 and the integrity processing unit 20 to the network24.

Computing devices 12 and 16 include a dispersed storage (DS) clientmodule 34, which enables the computing device to dispersed storage errorencode and decode data as subsequently described with reference to oneor more of FIGS. 3-8. In this example embodiment, computing device 16functions as a dispersed storage processing agent for computing device14. In this role, computing device 16 dispersed storage error encodesand decodes data on behalf of computing device 14. With the use ofdispersed storage error encoding and decoding, the DSN 10 is tolerant ofa significant number of storage unit failures (the number of failures isbased on parameters of the dispersed storage error encoding function)without loss of data and without the need for a redundant or backupcopies of the data. Further, the DSN 10 stores data for an indefiniteperiod of time without data loss and in a secure manner (e.g., thesystem is very resistant to unauthorized attempts at accessing thedata).

In operation, the managing unit 18 performs DS management services. Forexample, the managing unit 18 establishes distributed data storageparameters (e.g., vault creation, distributed storage parameters,security parameters, billing information, user profile information,etc.) for computing devices 12-14 individually or as part of a group ofuser devices. As a specific example, the managing unit 18 coordinatescreation of a vault (e.g., a virtual memory block associated with aportion of an overall namespace of the DSN) within the DSN memory 22 fora user device, a group of devices, or for public access and establishesper vault dispersed storage (DS) error encoding parameters for a vault.The managing unit 18 facilitates storage of DS error encoding parametersfor each vault by updating registry information of the DSN 10, where theregistry information may be stored in the DSN memory 22, a computingdevice 12-16, the managing unit 18, and/or the integrity processing unit20.

The DSN managing unit 18 creates and stores user profile information(e.g., an access control list (ACL)) in local memory and/or withinmemory of the DSN module 22. The user profile information includesauthentication information, permissions, and/or the security parameters.The security parameters may include encryption/decryption scheme, one ormore encryption keys, key generation scheme, and/or dataencoding/decoding scheme.

The DSN managing unit 18 creates billing information for a particularuser, a user group, a vault access, public vault access, etc. Forinstance, the DSN managing unit 18 tracks the number of times a useraccesses a non-public vault and/or public vaults, which can be used togenerate a per-access billing information. In another instance, the DSNmanaging unit 18 tracks the amount of data stored and/or retrieved by auser device and/or a user group, which can be used to generate aper-data-amount billing information.

As another example, the managing unit 18 performs network operations,network administration, and/or network maintenance. Network operationsincludes authenticating user data allocation requests (e.g., read and/orwrite requests), managing creation of vaults, establishingauthentication credentials for user devices, adding/deleting components(e.g., user devices, storage units, and/or computing devices with a DSclient module 34) to/from the DSN 10, and/or establishing authenticationcredentials for the storage units 36. Network administration includesmonitoring devices and/or units for failures, maintaining vaultinformation, determining device and/or unit activation status,determining device and/or unit loading, and/or determining any othersystem level operation that affects the performance level of the DSN 10.Network maintenance includes facilitating replacing, upgrading,repairing, and/or expanding a device and/or unit of the DSN 10.

The integrity processing unit 20 performs rebuilding of ‘bad’ or missingencoded data slices. At a high level, the integrity processing unit 20performs rebuilding by periodically attempting to retrieve/list encodeddata slices, and/or slice names of the encoded data slices, from the DSNmemory 22. For retrieved encoded slices, they are checked for errors dueto data corruption, outdated version, etc. If a slice includes an error,it is flagged as a ‘bad’ slice. For encoded data slices that were notreceived and/or not listed, they are flagged as missing slices. Badand/or missing slices are subsequently rebuilt using other retrievedencoded data slices that are deemed to be good slices to produce rebuiltslices. The rebuilt slices are stored in the DSN memory 22.

FIG. 2 is a schematic block diagram of an embodiment of a computing core26 that includes a processing module 50, a memory controller 52, mainmemory 54, a video graphics processing unit 55, an input/output (IO)controller 56, a peripheral component interconnect (PCI) interface 58,an IO interface module 60, at least one IO device interface module 62, aread only memory (ROM) basic input output system (BIOS) 64, and one ormore memory interface modules. The one or more memory interfacemodule(s) includes one or more of a universal serial bus (USB) interfacemodule 66, a host bus adapter (HBA) interface module 68, a networkinterface module 70, a flash interface module 72, a hard drive interfacemodule 74, and a DSN interface module 76.

The DSN interface module 76 functions to mimic a conventional operatingsystem (OS) file system interface (e.g., network file system (NFS),flash file system (FFS), disk file system (DFS), file transfer protocol(FTP), web-based distributed authoring and versioning (WebDAV), etc.)and/or a block memory interface (e.g., small computer system interface(SCSI), internet small computer system interface (iSCSI), etc.). The DSNinterface module 76 and/or the network interface module 70 may functionas one or more of the interface 30-33 of FIG. 1. Note that the IO deviceinterface module 62 and/or the memory interface modules 66-76 may becollectively or individually referred to as IO ports.

FIG. 3 is a schematic block diagram of an example of dispersed storageerror encoding of data. When a computing device 12 or 16 has data tostore it disperse storage error encodes the data in accordance with adispersed storage error encoding process based on dispersed storageerror encoding parameters. The dispersed storage error encodingparameters include an encoding function (e.g., information dispersalalgorithm, Reed-Solomon, Cauchy Reed-Solomon, systematic encoding,non-systematic encoding, on-line codes, etc.), a data segmentingprotocol (e.g., data segment size, fixed, variable, etc.), and per datasegment encoding values. The per data segment encoding values include atotal, or pillar width, number (T) of encoded data slices per encodingof a data segment i.e., in a set of encoded data slices); a decodethreshold number (D) of encoded data slices of a set of encoded dataslices that are needed to recover the data segment; a read thresholdnumber (R) of encoded data slices to indicate a number of encoded dataslices per set to be read from storage for decoding of the data segment;and/or a write threshold number (W) to indicate a number of encoded dataslices per set that must be accurately stored before the encoded datasegment is deemed to have been properly stored. The dispersed storageerror encoding parameters may further include slicing information (e.g.,the number of encoded data slices that will be created for each datasegment) and/or slice security information (e.g., per encoded data sliceencryption, compression, integrity checksum, etc.).

In the present example, Cauchy Reed-Solomon has been selected as theencoding function (a generic example is shown in FIG. 4 and a specificexample is shown in FIG. 5); the data segmenting protocol is to dividethe data object into fixed sized data segments; and the per data segmentencoding values include: a pillar width of 5, a decode threshold of 3, aread threshold of 4, and a write threshold of 4. In accordance with thedata segmenting protocol, the computing device 12 or 16 divides the data(e.g., a file (e.g., text, video, audio, etc.), a data object, or otherdata arrangement) into a plurality of fixed sized data segments (e.g., 1through Y of a fixed size in range of Kilo-bytes to Tera-bytes or more).The number of data segments created is dependent of the size of the dataand the data segmenting protocol.

The computing device 12 or 16 then disperse storage error encodes a datasegment using the selected encoding function (e.g., Cauchy Reed-Solomon)to produce a set of encoded data slices. FIG. 4 illustrates a genericCauchy Reed-Solomon encoding function, which includes an encoding matrix(EM), a data matrix (DM), and a coded matrix (CM). The size of theencoding matrix (EM) is dependent on the pillar width number (T) and thedecode threshold number (D) of selected per data segment encodingvalues. To produce the data matrix (DM), the data segment is dividedinto a plurality of data blocks and the data blocks are arranged into Dnumber of rows with Z data blocks per row. Note that Z is a function ofthe number of data blocks created from the data segment and the decodethreshold number (D). The coded matrix is produced by matrix multiplyingthe data matrix by the encoding matrix.

FIG. 5 illustrates a specific example of Cauchy Reed-Solomon encodingwith a pillar number (T) of five and decode threshold number of three.In this example, a first data segment is divided into twelve data blocks(D1-D12). The coded matrix includes five rows of coded data blocks,where the first row of X11-X14 corresponds to a first encoded data slice(EDS 1_1), the second row of X21-X24 corresponds to a second encodeddata slice (EDS 2_1), the third row of X31-X34 corresponds to a thirdencoded data slice (EDS 3_1), the fourth row of X41-X44 corresponds to afourth encoded data slice (EDS 4_1), and the fifth row of X51-X54corresponds to a fifth encoded data slice (EDS 5_1). Note that thesecond number of the EDS designation corresponds to the data segmentnumber.

Returning to the discussion of FIG. 3, the computing device also createsa slice name (SN) for each encoded data slice (EDS) in the set ofencoded data slices. A typical format for a slice name 60 is shown inFIG. 6. As shown, the slice name (SN) 60 includes a pillar number of theencoded data slice (e.g., one of 1-T), a data segment number (e.g., oneof 1-Y), a vault identifier (ID), a data object identifier (ID), and mayfurther include revision level information of the encoded data slices.The slice name functions as, at least part of, a DSN address for theencoded data slice for storage and retrieval from the DSN memory 22.

As a result of encoding, the computing device 12 or 16 produces aplurality of sets of encoded data slices, which are provided with theirrespective slice names to the storage units for storage. As shown, thefirst set of encoded data slices includes EDS 1_1 through EDS 5_1 andthe first set of slice names includes SN 1_1 through SN 5_1 and the lastset of encoded data slices includes EDS 1_Y through EDS 5_Y and the lastset of slice names includes SN 1_Y through SN 5_Y.

FIG. 7 is a schematic block diagram of an example of dispersed storageerror decoding of a data object that was dispersed storage error encodedand stored in the example of FIG. 4. In this example, the computingdevice 12 or 16 retrieves from the storage units at least the decodethreshold number of encoded data slices per data segment. As a specificexample, the computing device retrieves a read threshold number ofencoded data slices.

To recover a data segment from a decode threshold number of encoded dataslices, the computing device uses a decoding function as shown in FIG.8. As shown, the decoding function is essentially an inverse of theencoding function of FIG. 4. The coded matrix includes a decodethreshold number of rows (e.g., three in this example) and the decodingmatrix in an inversion of the encoding matrix that includes thecorresponding rows of the coded matrix. For example, if the coded matrixincludes rows 1, 2, and 4, the encoding matrix is reduced to rows 1, 2,and 4, and then inverted to produce the decoding matrix.

In some examples, note that dispersed or distributed storage network(DSN) memory includes one or more of a plurality of storage units (SUs)such as SUs 36 (e.g., that may alternatively be referred to adistributed storage and/or task network (DSTN) module that includes aplurality of distributed storage and/or task (DST) execution units 36that may be located at geographically different sites (e.g., one inChicago, one in Milwaukee, etc.). Each of the SUs (e.g., alternativelyreferred to as DST execution units in some examples) is operable tostore dispersed error encoded data and/or to execute, in a distributedmanner, one or more tasks on data. The tasks may be a simple function(e.g., a mathematical function, a logic function, an identify function,a find function, a search engine function, a replace function, etc.), acomplex function (e.g., compression, human and/or computer languagetranslation, text-to-voice conversion, voice-to-text conversion, etc.),multiple simple and/or complex functions, one or more algorithms, one ormore applications, etc.

FIG. 9 is a schematic block diagram of an embodiment of a dispersed ordistributed storage network (DSN) in accordance with the presentinvention. This diagram includes a schematic block diagram of anotherembodiment of a dispersed storage network that includes one or morestorage sets 1-2, the network 24 of FIG. 1, and the distributed storage(DS) client module 34 of FIG. 1 and/or computing device 16 of FIG. 1.Note that such operations, functions, etc. as described herein as beingperformed by such a DS client module 34 may alternatively be performedby computing device 16. Each storage set includes a set of storage units(SUs) 1-n+1. As such, each set of SUs a number of SU set is greater thanan information dispersal algorithm (IDA) width number n. Each SU mayinclude a plurality of memory devices, where each memory device isassociated with a set of memory devices of the set of SUs. Each set ofmemory devices includes a number of memory devices that is greater thanthe IDA width number. Each set of memory devices is associated with aunique dispersed storage network (DSN) address range corresponding(e.g., common for each memory device of the set of memory devices). Forexample, each SU includes a first memory device that is associated witha first common DSN address range and a second memory device that isassociated with a second common DSN address range. Alternatively, theset of SUs includes fewer than n+1 SUs, where the set of SUs includes aplurality of sets of memory devices where each set of memory devicesincludes a number of memory devices that is greater than the IDA widthnumber. Each SU may be implemented utilizing the SU 36 of FIG. 1. TheDSN functions to maintain data integrity of stored data, where the oneor more storage sets mirror stored data when at least two storage setsare utilized.

In an example of operation of the maintaining of the data integrity, theDS client module 34 detects a potential storage issue with a memorydevice of a SU, where the SU includes a plurality of memory devices thatincludes the memory device. The detecting includes at least one ofinterpreting an error message, initiating a test, interpreting a testresult, interpreting a memory device replacement schedule, determiningthat an age of the memory device compares unfavorably to a maximum agethreshold level, and receiving a request. For example, the DS clientmodule 34 detects that memory 2_1 of the SU 2 of the storage set 1 isassociated with the potential storage issue based on interpreting a testresult.

Having detected the potential storage issue, the DS client module 34determines whether to temporarily transfer stored encoded data slicesassociated with the memory device to another memory device of theplurality of memory devices of the SU. The determining includesindicating to transfer to the other memory device when the other memorydevice has sufficient unused storage capacity. For instance, the DSclient module 34 indicates to transfer stored encoded data slices 2 fromthe memory device 2_1 to the memory device 2_2 when the memory device2_2 has sufficient storage capacity.

When not transferring the stored encoded data slices to the other memorydevice of the SU, the DS client module 34 identifies at least onealternate storage location. The identifying may be based on one or moreof a predetermination, a round-robin alternative location list,interpreting a schedule, interpreting a portion of a system registry,determining available storage capacity of a candidate storage location,and a request. The alternate storage locations include candidates ofanother SU of the set of SUs, and a SU of another storage set. Forexample, the DS client module 34 selects the memory device n+1_1 of theSU n+1 when the memory device n+1_1 has sufficient storage capacity.

Having identified the at least one alternate storage location, the DSclient module 34 facilitates transfer of stored encoded data slices fromthe memory device to the identified at least one alternate storagelocation. The facilitating includes one or more of causing encryption ofone or more of the stored encoded data slices to produce encryptedencoded data slices, causing transfer of the encrypted encoded dataslices to the identified at least one alternate storage location. Forexample, the SU 2 generates a secret encryption key, temporarily storesthe secret encryption key, encrypts the stored encoded data slices 2retrieved from the memory device 2_1 using the secret encryption key toproduce encrypted encoded data slices 2, issues, via the network 24, oneor more write slice requests to the SU n+1, where the write slicerequests includes the encrypted encoded data slices 2, and temporarilystoring, by the SU n+1, received encrypted encoded data slices 2 in thememory device n+1_1.

When detecting that the potential storage issue has subsided, the DSclient module 34 facilitates transfer of the stored encoded data slicesfrom one of the at least one alternate storage locations to the memorydevice of the SU. For example, the SU 2 issues, via the network 24, readslice requests to the SU n+1_1, receives the encrypted encoded dataslices 2, recovers the saved secret encryption key, decrypts theencrypted encoded data slices 2 using the saved secret encryption key toreproduce the encoded data slices 2, and stores the reproduced encodeddata slices 2 and the memory 2_1. Alternatively, the SU 2 stores thereproduced encoded data slices 2 in another memory device (e.g., areplacement memory device, another existing memory device withsufficient storage capacity) of the SU 2.

In an example of operation and implementation, a computing deviceincludes an interface configured to interface and communicate with adispersed or distributed storage network (DSN), a memory that storesoperational instructions, and a processing module, processor, and/orprocessing circuitry operably coupled to the interface and memory. Theprocessing module, processor, and/or processing circuitry is configuredto execute the operational instructions to perform various operations,functions, etc. In some examples, the processing module, processor,and/or processing circuitry, when operable within the computing devicebased on the operational instructions, is configured to perform variousoperations, functions, etc. In certain examples, the processing module,processor, and/or processing circuitry, when operable within thecomputing device is configured to perform one or more functions that mayinclude generation of one or more signals, processing of one or moresignals, receiving of one or more signals, transmission of one or moresignals, interpreting of one or more signals, etc. and/or any otheroperations as described herein and/or their equivalents.

In an example of operation and implementation, a computing device (e.g.,computing device 16 of FIG. 1, FIG. 9, and/or any other diagram,example, embodiment, equivalent, etc. as described herein) is configuredto detect a potentially adverse storage issue with a memory device of astorage unit (SU) of one or more sets of storage units (SUs) within theDSN. Note that a data object is segmented into a plurality of datasegments, and a data segment of the plurality of data segments isdispersed error encoded in accordance with dispersed error encodingparameters to produce a set of encoded data slices (EDSs) that aredistributedly stored within the one or more sets of storage units SUswithin the DSN. The computing device is also configured to determinewhether to transfer at least one EDSs of the set of EDSs that isassociated with the memory device of the SU of the one or more sets ofSUs within the DSN to another memory device of the SU of the one or moresets of SUs within the DSN for temporary storage therein.

Based on a determination not to transfer the at least one EDSs of theset of EDSs that is associated with the memory device of the SU of theone or more sets of SUs within the DSN to the other memory device of theSU of the one or more sets of SUs within the DSN for temporary storagetherein, the computing device is also configured to identify at leastone alternate storage location within the DSN to store temporarily theat least one EDSs of the set of EDSs that is associated with the memorydevice of the SU of the one or more sets of SUs within the DSN.

The computing device is also configured to facilitate transfer of the atleast one EDSs of the set of EDSs that is associated with the memorydevice of the SU of the one or more sets of SUs within the DSN to the atleast one alternate storage location within the DSN for temporarystorage therein.

Based on detection that the potentially adverse storage issue with thememory device of the SU of the one or more sets of SUs within the DSNhas subsided, the computing device is also configured to facilitatetransfer of the at least one EDSs of the set of EDSs from the at leastone alternate storage location within the DSN back to the memory deviceof the SU of the one or more sets of SUs within the DSN.

In some examples, the computing device is further configured to detectthe potentially adverse storage issue with the memory device of the SUof the one or more sets of SUs within the DSN based on interpreting anerror message, initiating a test, interpreting a test result,interpreting a memory device replacement schedule, determining that anage of the memory device compares unfavorably to a maximum age thresholdlevel, and/or receiving a request.

In even other examples, the computing device is further configured toidentify the at least one alternate storage location within the DSNbased on a predetermination, a round-robin alternative location list,interpreting a memory device replacement schedule, interpreting aportion of a system registry, determining available storage capacity ofa candidate storage location, and/or a request.

Also, in yet other examples, the computing device is further configuredto facilitate transfer of the at least one EDSs of the set of EDSs thatis associated with the memory device of the SU of the one or more setsof SUs to the at least one alternate storage location within the DSN fortemporary storage therein based on causing encryption of one or more ofthe set of EDSs to produce encrypted EDSs and/or causing transfer of theencrypted EDSs to the at least one alternate storage location.

In some examples, with respect to a data object, the data object issegmented into a plurality of data segments, and a data segment of theplurality of data segments is dispersed error encoded in accordance withdispersed error encoding parameters to produce a set of encoded dataslices (EDSs) (e.g., in some instances, the set of EDSs aredistributedly stored in a plurality of storage units (SUs) within theDSN). In some examples, the set of EDSs is of pillar width. Also, withrespect to certain implementations, note that the decode thresholdnumber of EDSs are needed to recover the data segment, and a readthreshold number of EDSs provides for reconstruction of the datasegment. Also, a write threshold number of EDSs provides for asuccessful transfer of the set of EDSs from a first at least onelocation in the DSN to a second at least one location in the DSN. Theset of EDSs is of pillar width and includes a pillar number of EDSs.Also, in some examples, each of the decode threshold, the readthreshold, and the write threshold is less than the pillar number. Also,in some particular examples, the write threshold number is greater thanor equal to the read threshold number that is greater than or equal tothe decode threshold number.

Note that the computing device as described herein may be located at afirst premises that is remotely located from a second premisesassociated with at least one other SU, dispersed storage (DS) unit,computing device, at least one SU of a plurality of SUs within the DSN(e.g., such as a plurality of SUs that are implemented to storedistributedly a set of EDSs), etc. In addition, note that such acomputing device as described herein may be implemented as any of anumber of different devices including a managing unit that is remotelylocated from another SU, DS unit, computing device, etc. within the DSNand/or other device within the DSN, an integrity processing unit that isremotely located from another computing device and/or other devicewithin the DSN, a scheduling unit that is remotely located from anothercomputing device and/or SU within the DSN, and/or other device. Also,note that such a computing device as described herein may be of any of avariety of types of devices as described herein and/or their equivalentsincluding a DS unit and/or SU included within any group and/or set of DSunits and/or SUs within the DSN, a wireless smart phone, a laptop, atablet, a personal computers (PC), a work station, and/or a video gamedevice, and/or any type of computing device or communication device.Also, note also that the DSN may be implemented to include and/or bebased on any of a number of different types of communication systemsincluding a wireless communication system, a wire lined communicationsystem, a non-public intranet system, a public internet system, a localarea network (LAN), and/or a wide area network (WAN). Also, in someexamples, any device configured to support communications within such aDSN may be also be configured to and/or specifically implemented tosupport communications within a satellite communication system, awireless communication system, a wired communication system, afiber-optic communication system, and/or a mobile communication system(and/or any other type of communication system implemented using anytype of communication medium or media).

FIG. 10 is a flowchart illustrating an example of maintaining dataintegrity in accordance with the present invention. This diagramincludes a flowchart illustrating an example of maintaining dataintegrity. The method 1000 begins or continues at a step 1010 where aprocessing module (e.g., of a distributed storage (DS) client moduleand/or computing device) detects a potential storage issue with a memorydevice of a storage unit. The detecting includes at least one ofreceiving an error message, interpreting a test result, interpreting amemory replacement schedule, and/or receiving a request.

The method 1000 continues at the step 1020 where the processing moduledetermines whether to temporarily transfer stored encoded data slicesassociated with the memory device to another memory device of thestorage unit. The determining includes indicating that the transfer whenthe other memory device has insufficient unused storage capacity forstorage of the stored encoded data slices.

When not temporarily transferring the stored encoded data slices to theother memory device of the storage unit, the method 1000 continues atthe step 1030 where the processing module identifies at least onealternate storage location. The identifying may be based on one or moreof a predetermination, a round-robin alternative location list, aschedule, a system registry, and a request.

The method 1000 continues at the step 1040 where the processing modulefacilitates transfer of the stored encoded data slices from the memorydevice to the identified at least one alternate storage location. Forexample, the processing module facilitates encryption of each encodeddata slices, facilitates issuing of a write slice request to the atleast one alternate storage location, where the write slice requestincludes the encrypted encoded data slices, and facilitates saving of anencryption key associated with the encryption and an identifier of thealternate storage location.

When detecting that the potential storage issue has subsided, the method1000 continues at the step 1050 where the processing module facilitatestransfer of the stored encoded data slices from one of the at least onealternate storage location to the memory device of the storage unit. Forexample, the processing module identifies the alternate storagelocation, facilitates recovery of the encryption key, facilitatesissuing of a read slice request to recover the encrypted encoded dataslices, facilitates decryption of the recovered encryption encoded dataslices from the read slice responses using the recovered encryption keyto reproduce the encoded data slices, and facilitate storage of thereproduced encoded data slices in the memory device and/or a replacementmemory device. Alternatively, or in addition to, the processing modulefacilitates deletion of the stored encoded data slices from each of theat least one alternate storage locations after confirmation of transferto the memory device.

FIG. 11 is a diagram illustrating an embodiment of a method 1100 forexecution by one or more computing devices in accordance with thepresent invention. The method 1100 operates in step 1110 by detecting apotentially adverse storage issue with a memory device of a storage unit(SU) of one or more sets of storage units (SUs) within a dispersed ordistributed storage network (DSN). Note that a data object is segmentedinto a plurality of data segments, and a data segment of the pluralityof data segments is dispersed error encoded in accordance with dispersederror encoding parameters to produce a set of encoded data slices (EDSs)that are distributedly stored within the one or more sets of storageunits SUs within the DSN;

The method 1100 then continues in step 1120 by determining whether totransfer at least one EDSs of the set of EDSs that is associated withthe memory device of the SU of the one or more sets of SUs within theDSN to another memory device of the SU of the one or more sets of SUswithin the DSN for temporary storage therein

Based on a determination to transfer the at least one EDSs of the set ofEDSs that is associated with the memory device of the SU of the one ormore sets of SUs within the DSN to the other memory device of the SU ofthe one or more sets of SUs within the DSN for temporary storage therein(yes branch from step 1130), the method 1100 operates in step 1132 bytransferring the at least one EDSs from the memory device of the SU tothe other memory device of the SU.

Based on a determination not to transfer the at least one EDSs of theset of EDSs that is associated with the memory device of the SU of theone or more sets of SUs within the DSN to the other memory device of theSU of the one or more sets of SUs within the DSN for temporary storagetherein (no branch from step 1130), the method 1100 operates in step1140 by identifying at least one alternate storage location within theDSN to store temporarily the at least one EDSs of the set of EDSs thatis associated with the memory device of the SU of the one or more setsof SUs within the DSN.

The method 1100 then continues in step 1150 by facilitating (e.g., viaan interface of the computing device that is configured to interface andcommunicate with the DSN) transfer of the at least one EDSs of the setof EDSs that is associated with the memory device of the SU of the oneor more sets of SUs within the DSN to the at least one alternate storagelocation within the DSN for temporary storage therein.

The method 1100 operates in step 1160 by monitoring the potentiallyadverse storage issue with the memory device of the SU of one or moresets of SUs within the DSN. Based on detection that the potentiallyadverse storage issue with the memory device of the SU of the one ormore sets of SUs within the DSN has not subsided (no branch from step1170), the method 1100 then operates by looping back to the step 1160 oralternatively operates by ending.

Based on detection that the potentially adverse storage issue with thememory device of the SU of the one or more sets of SUs within the DSNhas subsided (yes branch from step 1170), the method 1100 then operatesin step 1180 by facilitating (e.g., via the interface) transfer of theat least one EDSs of the set of EDSs from the at least one alternatestorage location within the DSN back to the memory device or another ofthe SU of the one or more sets of SUs within the DSN.

This disclosure presents, among other things, various novel solutionsthat operate by finding alternate storage locations to support failingdisk migration. For example, a failing disk migration feature attemptsto pro-actively identify memory devices that are about to fail andtransfer the data present on them to neighboring memory devices within astorage unit (SU). This serves the function of avoiding a costlyrebuild, since upon replacement of the failing memory device, the slicescan be transferred back. However, the availability of this feature isdependent on each SU having spare and unused capacity at the time amemory device is predicted to fail. If all memory devices in a SU areclose to 100% of their capacity, the following alternate storagelocations may be utilized: (1) a vault dedicated to the purposes ofstoring slices from failing memory devices, (2) another SU (ranked byproximity, e.g. favoring a SU in the same rack, or site vs. one that isremote or otherwise connected by a slow or expensive link), and/or (3)another SU as part of a Target Width set of SUs.

In some examples, note that strategy (3) is preferable over strategies(1) and (2), because requesting clients can still recover/access thisdata while it is part of one of the SUs in the same target width set ofSUs that had the failing memory device. In cases 1 and 2, because thelocation is not necessarily trusted to know the slice, and because theclient will not be in a position to see them until they are transferredback, the SU may apply an encryption key to the slices prior totransmitting them to the alternate location. The SU will then use thiskey to decrypt them when they are transferred back. Further, thisencryption key (or one similarly generated) may also be applied as partof a signature or hash-based message authentication code (HMAC)algorithm to verify the integrity of the slices when they are returned(following replacement of the failed memory device).

It is noted that terminologies as may be used herein such as bit stream,stream, signal sequence, etc. (or their equivalents) have been usedinterchangeably to describe digital information whose contentcorresponds to any of a number of desired types (e.g., data, video,speech, audio, etc. any of which may generally be referred to as‘data’).

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “configured to”, “operably coupled to”, “coupled to”, and/or“coupling” includes direct coupling between items and/or indirectcoupling between items via an intervening item (e.g., an item includes,but is not limited to, a component, an element, a circuit, and/or amodule) where, for an example of indirect coupling, the intervening itemdoes not modify the information of a signal but may adjust its currentlevel, voltage level, and/or power level. As may further be used herein,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two items inthe same manner as “coupled to”. As may even further be used herein, theterm “configured to”, “operable to”, “coupled to”, or “operably coupledto” indicates that an item includes one or more of power connections,input(s), output(s), etc., to perform, when activated, one or more itscorresponding functions and may further include inferred coupling to oneor more other items. As may still further be used herein, the term“associated with”, includes direct and/or indirect coupling of separateitems and/or one item being embedded within another item.

As may be used herein, the term “compares favorably”, indicates that acomparison between two or more items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1. As maybe used herein, the term “compares unfavorably”, indicates that acomparison between two or more items, signals, etc., fails to providethe desired relationship.

As may also be used herein, the terms “processing module”, “processingcircuit”, “processor”, and/or “processing unit” may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may be, or furtherinclude, memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of another processing module, module, processing circuit,and/or processing unit. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the figures. Such a memorydevice or memory element can be included in an article of manufacture.

One or more embodiments have been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claims. Further, the boundariesof these functional building blocks have been arbitrarily defined forconvenience of description. Alternate boundaries could be defined aslong as the certain significant functions are appropriately performed.Similarly, flow diagram blocks may also have been arbitrarily definedherein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence couldhave been defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claims. One of average skill in the art will alsorecognize that the functional building blocks, and other illustrativeblocks, modules and components herein, can be implemented as illustratedor by discrete components, application specific integrated circuits,processors executing appropriate software and the like or anycombination thereof.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with other routines. In this context, “start” indicates thebeginning of the first step presented and may be preceded by otheractivities not specifically shown. Further, the “continue” indicationreflects that the steps presented may be performed multiple times and/ormay be succeeded by other activities not specifically shown. Further,while a flow diagram indicates a particular ordering of steps, otherorderings are likewise possible provided that the principles ofcausality are maintained.

The one or more embodiments are used herein to illustrate one or moreaspects, one or more features, one or more concepts, and/or one or moreexamples. A physical embodiment of an apparatus, an article ofmanufacture, a machine, and/or of a process may include one or more ofthe aspects, features, concepts, examples, etc. described with referenceto one or more of the embodiments discussed herein. Further, from figureto figure, the embodiments may incorporate the same or similarly namedfunctions, steps, modules, etc. that may use the same or differentreference numbers and, as such, the functions, steps, modules, etc. maybe the same or similar functions, steps, modules, etc. or differentones.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of theembodiments. A module implements one or more functions via a device suchas a processor or other processing device or other hardware that mayinclude or operate in association with a memory that stores operationalinstructions. A module may operate independently and/or in conjunctionwith software and/or firmware. As also used herein, a module may containone or more sub-modules, each of which may be one or more modules.

As may further be used herein, a computer readable memory includes oneor more memory elements. A memory element may be a separate memorydevice, multiple memory devices, or a set of memory locations within amemory device. Such a memory device may be a read-only memory, randomaccess memory, volatile memory, non-volatile memory, static memory,dynamic memory, flash memory, cache memory, and/or any device thatstores digital information. The memory device may be in a form a solidstate memory, a hard drive memory, cloud memory, thumb drive, servermemory, computing device memory, and/or other physical medium forstoring digital information.

While particular combinations of various functions and features of theone or more embodiments have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent disclosure is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A computing device comprising: an interfaceconfigured to interface and communicate with a dispersed or distributedstorage network (DSN); memory that stores operational instructions; andprocessing circuitry operably coupled to the interface and to thememory, wherein the processing circuitry is configured to execute theoperational instructions to: detect a potentially adverse storage issuewith a memory device of a storage unit (SU) of one or more sets ofstorage units (SUs) within the DSN, wherein a data object is segmentedinto a plurality of data segments, wherein a data segment of theplurality of data segments is dispersed error encoded in accordance withdispersed error encoding parameters to produce a set of encoded dataslices (EDSs) that are distributedly stored within the one or more setsof storage units SUs within the DSN, wherein the potentially adversestorage issue is based on at least one of predicted failure of thememory device, an age of the memory device being greater than or equalto a maximum age threshold level, or an indication that the memorydevice is failing; determine whether to transfer at least one EDSs ofthe set of EDSs that is associated with the memory device of the SU ofthe one or more sets of SUs within the DSN to another memory device ofthe SU of the one or more sets of SUs within the DSN for temporarystorage therein; based on a determination not to transfer the at leastone EDSs of the set of EDSs that is associated with the memory device ofthe SU of the one or more sets of SUs within the DSN to the anothermemory device of the SU of the one or more sets of SUs within the DSNfor temporary storage therein, identify at least one alternate storagelocation within the DSN to store temporarily the at least one EDSs ofthe set of EDSs that is associated with the memory device of the SU ofthe one or more sets of SUs within the DSN; facilitate transfer of theat least one EDSs of the set of EDSs that is associated with the memorydevice of the SU of the one or more sets of SUs within the DSN to the atleast one alternate storage location within the DSN for temporarystorage therein; and based on detection that the potentially adversestorage issue with the memory device of the SU of the one or more setsof SUs within the DSN has subsided, facilitate transfer of the at leastone EDSs of the set of EDSs from the at least one alternate storagelocation within the DSN back to the memory device of the SU of the oneor more sets of SUs within the DSN.
 2. The computing device of claim 1,wherein the processing circuitry is further configured to execute theoperational instructions to: detect the potentially adverse storageissue with the memory device of the SU of the one or more sets of SUswithin the DSN based on at least one of interpreting an error message,initiating a test, interpreting a test result, interpreting a memorydevice replacement schedule, determining that an age of the memorydevice compares unfavorably to a maximum age threshold level, orreceiving a request.
 3. The computing device of claim 1, wherein theprocessing circuitry is further configured to execute the operationalinstructions to: identify the at least one alternate storage locationwithin the DSN based on at least one of a predetermination, around-robin alternative location list, interpreting a memory devicereplacement schedule, interpreting a portion of a system registry,determining available storage capacity of a candidate storage location,or a request.
 4. The computing device of claim 1, wherein the processingcircuitry is further configured to execute the operational instructionsto: facilitate transfer of the at least one EDSs of the set of EDSs thatis associated with the memory device of the SU of the one or more setsof SUs to the at least one alternate storage location within the DSN fortemporary storage therein based on at least one of causing encryption ofone or more of the set of EDSs to produce encrypted EDSs or causingtransfer of the encrypted EDSs to the at least one alternate storagelocation.
 5. The computing device of claim 1, wherein: a decodethreshold number of EDSs are needed to recover the data segment; a readthreshold number of EDSs provides for reconstruction of the datasegment; a write threshold number of EDSs provides for a successfultransfer of the set of EDSs from a first at least one location in theDSN to a second at least one location in the DSN; the set of EDSs is ofpillar width and includes a pillar number of EDSs; each of the decodethreshold number, the read threshold number, and the write thresholdnumber is less than the pillar number; and the write threshold number isgreater than or equal to the read threshold number that is greater thanor equal to the decode threshold number.
 6. The computing device ofclaim 1, wherein the computing device is located at a first premisesthat is remotely located from a second premises of at least one SU ofthe one or more sets of SUs within the DSN.
 7. The computing device ofclaim 1 further comprising: a SU of the one or more sets of SUs withinthe DSN, a wireless smart phone, a laptop, a tablet, a personalcomputers (PC), a work station, or a video game device.
 8. The computingdevice of claim 1, wherein the DSN includes at least one of a wirelesscommunication system, a wire lined communication system, a non-publicintranet system, a public internet system, a local area network (LAN),or a wide area network (WAN).
 9. A computing device comprising: aninterface configured to interface and communicate with a dispersed ordistributed storage network (DSN); memory that stores operationalinstructions; and processing circuitry operably coupled to the interfaceand to the memory, wherein the processing circuitry is configured toexecute the operational instructions to: detect a potentially adversestorage issue with a memory device of a storage unit (SU) of one or moresets of storage units (SUs) within the DSN based on at least one ofinterpreting an error message, initiating a test, interpreting a testresult, interpreting a memory device replacement schedule, determiningthat an age of the memory device compares unfavorably to a maximum agethreshold level, or receiving a request, wherein a data object issegmented into a plurality of data segments, wherein a data segment ofthe plurality of data segments is dispersed error encoded in accordancewith dispersed error encoding parameters to produce a set of encodeddata slices (EDSs) that are distributedly stored within the one or moresets of storage units SUs within the DSN, wherein the potentiallyadverse storage issue is based on at least one of predicted failure ofthe memory device, an age of the memory device being greater than orequal to a maximum age threshold level, or an indication that the memorydevice is failing; determine whether to transfer at least one EDSs ofthe set of EDSs that is associated with the memory device of the SU ofthe one or more sets of SUs within the DSN to another memory device ofthe SU of the one or more sets of SUs within the DSN for temporarystorage therein; based on a determination not to transfer the at leastone EDSs of the set of EDSs that is associated with the memory device ofthe SU of the one or more sets of SUs within the DSN to the anothermemory device of the SU of the one or more sets of SUs within the DSNfor temporary storage therein, identify at least one alternate storagelocation within the DSN to store temporarily the at least one EDSs ofthe set of EDSs that is associated with the memory device of the SU ofthe one or more sets of SUs within the DSN; facilitate transfer of theat least one EDSs of the set of EDSs that is associated with the memorydevice of the SU of the one or more sets of SUs within the DSN to the atleast one alternate storage location within the DSN for temporarystorage therein based on at least one of causing encryption of one ormore of the set of EDSs to produce encrypted EDSs or causing transfer ofthe encrypted EDSs to the at least one alternate storage location; andbased on detection that the potentially adverse storage issue with thememory device of the SU of the one or more sets of SUs within the DSNhas subsided, facilitate transfer of the at least one EDSs of the set ofEDSs from the at least one alternate storage location within the DSNback to the memory device of the SU of the one or more sets of SUswithin the DSN.
 10. The computing device of claim 9, wherein theprocessing circuitry is further configured to execute the operationalinstructions to: identify the at least one alternate storage locationwithin the DSN based on at least one of a predetermination, around-robin alternative location list, interpreting the memory devicereplacement schedule, interpreting a portion of a system registry,determining available storage capacity of a candidate storage location,or another request.
 11. The computing device of claim 9, wherein: adecode threshold number of EDSs are needed to recover the data segment;a read threshold number of EDSs provides for reconstruction of the datasegment; a write threshold number of EDSs provides for a successfultransfer of the set of EDSs from a first at least one location in theDSN to a second at least one location in the DSN; the set of EDSs is ofpillar width and includes a pillar number of EDSs; each of the decodethreshold number, the read threshold number, and the write thresholdnumber is less than the pillar number; and the write threshold number isgreater than or equal to the read threshold number that is greater thanor equal to the decode threshold number.
 12. The computing device ofclaim 9 further comprising: a SU of the one or more sets of SUs withinthe DSN, a wireless smart phone, a laptop, a tablet, a personalcomputers (PC), a work station, or a video game device.
 13. Thecomputing device of claim 9, wherein the DSN includes at least one of awireless communication system, a wire lined communication system, anon-public intranet system, a public internet system, a local areanetwork (LAN), or a wide area network (WAN).
 14. A method for executionby a computing device, the method comprising: detecting a potentiallyadverse storage issue with a memory device of a storage unit (SU) of oneor more sets of storage units (SUs) within a dispersed or distributedstorage network (DSN), wherein a data object is segmented into aplurality of data segments, wherein a data segment of the plurality ofdata segments is dispersed error encoded in accordance with dispersederror encoding parameters to produce a set of encoded data slices (EDSs)that are distributedly stored within the one or more sets of storageunits SUs within the DSN, wherein the potentially adverse storage issueis based on at least one of predicted failure of the memory device, anage of the memory device being greater than or equal to a maximum agethreshold level, or an indication that the memory device is failing;determining whether to transfer at least one EDSs of the set of EDSsthat is associated with the memory device of the SU of the one or moresets of SUs within the DSN to another memory device of the SU of the oneor more sets of SUs within the DSN for temporary storage therein; basedon a determination not to transfer the at least one EDSs of the set ofEDSs that is associated with the memory device of the SU of the one ormore sets of SUs within the DSN to the another memory device of the SUof the one or more sets of SUs within the DSN for temporary storagetherein, identifying at least one alternate storage location within theDSN to store temporarily the at least one EDSs of the set of EDSs thatis associated with the memory device of the SU of the one or more setsof SUs within the DSN; facilitating, via an interface of the computingdevice that is configured to interface and communicate with the DSN,transfer of the at least one EDSs of the set of EDSs that is associatedwith the memory device of the SU of the one or more sets of SUs withinthe DSN to the at least one alternate storage location within the DSNfor temporary storage therein; and based on detection that thepotentially adverse storage issue with the memory device of the SU ofthe one or more sets of SUs within the DSN has subsided, facilitating,via the interface, transfer of the at least one EDSs of the set of EDSsfrom the at least one alternate storage location within the DSN back tothe memory device or another of the SU of the one or more sets of SUswithin the DSN.
 15. The method of claim 14 further comprising: detectingthe potentially adverse storage issue with the memory device of the SUof the one or more sets of SUs within the DSN based on at least one ofinterpreting an error message, initiating a test, interpreting a testresult, interpreting a memory device replacement schedule, determiningthat an age of the memory device compares unfavorably to a maximum agethreshold level, or receiving a request.
 16. The method of claim 14further comprising: identifying the at least one alternate storagelocation within the DSN based on at least one of a predetermination, around-robin alternative location list, interpreting a memory devicereplacement schedule, interpreting a portion of a system registry,determining available storage capacity of a candidate storage location,or a request.
 17. The method of claim 14 further comprising:facilitating, via the interface, transfer of the at least one EDSs ofthe set of EDSs that is associated with the memory device of the SU ofthe one or more sets of SUs to the at least one alternate storagelocation within the DSN for temporary storage therein based on at leastone of causing encryption of one or more of the set of EDSs to produceencrypted EDSs or causing transfer of the encrypted EDSs to the at leastone alternate storage location.
 18. The method of claim 14, wherein: adecode threshold number of EDSs are needed to recover the data segment;a read threshold number of EDSs provides for reconstruction of the datasegment; a write threshold number of EDSs provides for a successfultransfer of the set of EDSs from a first at least one location in theDSN to a second at least one location in the DSN; the set of EDSs is ofpillar width and includes a pillar number of EDSs; each of the decodethreshold number, the read threshold number, and the write thresholdnumber is less than the pillar number; and the write threshold number isgreater than or equal to the read threshold number that is greater thanor equal to the decode threshold number.
 19. The method of claim 14,wherein the computing device includes a SU of the one or more sets ofSUs within the DSN, a wireless smart phone, a laptop, a tablet, apersonal computers (PC), a work station, or a video game device.
 20. Themethod of claim 14, wherein the DSN includes at least one of a wirelesscommunication system, a wire lined communication system, a non-publicintranet system, a public internet system, a local area network (LAN),or a wide area network (WAN).